Ken Livingstone has claimed he pays enough tax to fund a new £2.5 billion aircraft carrier.

Labour's mayoral candidate issued a robust defence of his finances, insisting he paid 35 per cent of his earnings in tax.

But his claims were met with boos and cries of "champagne socialist" at the Evening Standard debate last night. The event was dominated by the tax avoidance row which has plagued Mr Livingstone's campaign.

Boris Johnson also came under fire for failing to get back to London more quickly during last summer's riots. The Mayor was accused of dragging his feet by taking three days to fly back from a holiday in Canada.

But Mr Livingstone's defence of his tax position met the biggest audience reaction. His claims came as every other senior politician prepared to publish full details of their tax statements. All the mayoral candidates opened their books last week but Mr Livingstone only gave partial details.

He has taken a hit in the polls over the issue, as half of Londoners said they are less likely to trust him as a result.

But a bullish Mr Livingstone insisted he had already "lanced the boil" over the affair, and expressed surprise he was paying so much tax.

"I immediately discovered I've been paying 35 per cent tax, so much bloody tax the Government should have been able to get another one of these aircraft carriers without planes," he said.

He has faced charges of hypocrisy for channelling his income through a company, having previously attacked tax avoiders as "rich bastards". Senior campaign sources indicated he would be prepared to publish more information if pressure increased. His claims come amid government moves toward a US-style system where all senior politicians reveal their earnings.

David Cameron said it was "increasingly likely" he will take the unprecedented step of revealing his annual tax. Lib-Dem leader Nick Clegg welcomed the move and Labour chief Ed Miliband said he would be happy to follow suit. It emerged today that Mr Livingstone failed to disclose tens of thousands of pounds in earnings. His campaign team was forced to amend his published tax statement to rectify the error.

Documents seen by the Standard reveal that he received a £71,746 resettlement grant from the Greater London Authority in the 2008/09 financial year after being defeated by Mr Johnson.

But in the accounts Mr Livingstone released last week he claimed that he only earned £21,645 then. Tory MP Priti Patel said: "This is further dodgy dealings from Ken. He owes it to London's electorate to publish his earnings."

The Government's replacement aircraft carrier programme costs £5 billion for two ships, though the National Audit Office said that could double.